Gyr Falcon sightings in the UK (1 Viewer)

[wolfbirder]

I know this is widely discussed at sighting times, but I am not sure if people understand the difficulty of seperating true wild birds from escaped falconers birds. Hope that does not sound patronising, I certainly find the views and counter views interesting and I have learnt a considerable amount recently.

There have been recent birds on Islay and Glamorgan, and possibly the old traditional favoured area of Cornish coast.

I really do wonder if it is possible to seperate wild birds from falconer's escapes even if they are at feasable locations. Gyr's are great wanderers and may conceivably travel from coast to coast in a short time.

People argue that birds are likely to be wild if they have no jesses / anklets on, but whilst these can detach, rings should not come off during a birds lifetime. However, unless good close views are obtained this can be a difficult thing to achieve, and the rings on occasion can be hidden by the feathered tarsi according to falconer's. I would have thought any rings would be lower on the bare section of leg near the feet (by the law of gravity) but it is feasable they cannot be seen even at close range. Falconer's birds can be transmitter-fitted but these are very difficult to see, and a bird can easily be lost and be quickly out of transmitter range when being flown.

To make matters worse falconers who breed birds for sale to rich arabian customers (in the main) often keep young Gyr's in hack-pens out in the wilds of Scotland for example, so they retain their natural wild behaviour. Apparently, whilst in hack pens they can on rare occasion go missing for 2-3 days at a time, though they will usually stay near to the hack pen. This clearly would not help birders in distinguishing such birds from wild ones !

And then there is the situation with hybrids. Although pure white Gyr's are bred (that being the most popular colour phase amongst purchasers), these ('pure' Gyr) are quite rare as they are apparently more susceptible to disease in captivity compared to Saker's for example, and 'pure' captive Gyr's get more quickly stressed in captivity compared to hybrids. Most birds are therefore hybridised to a Gyr-Saker hybrid (or less often Gyr-Peregrine). And then it is not a simple gene split. And as the Saker is slimmer than the Gyr you may think a hybrid would still be identifiable. But whilst some Gyr-Saker hybrids are 50-50, most appear to be 75-25 or 7/8th's in favour of Gyr, but I have read of 15/16th's Gyr-Saker hybrid. With the latter three ratio hyrids it appears that it is virtually impossible to differentiate. Apparently such hybrid birds have been sold to well-known falconers in the Uk and abroad, under the guise of 'pure' Gyr. So if they cannot distinguish whilst held in the hand, what chance have birders got of clarifying identity? Obviously key features include girth and general body shape, but with such hybrids it can be virtually impossible to tell the difference. Some subtle hints of hybrid include a mixture of reddish-brown and brown upperparts on pale phase birds - the sporadic rufous colouration hints at Saker genes in the hybrid. For anyone who thinks it is going to be easy, check out the gallery of Gyr's and then Gyr-Saker hybrids at www.gyrfalcons.co.uk

I have only seen Gyr's twice, the Stepper Point bird and Gower bird, both genuinely look good candidates for being true wild birds for me (good body proportions and colouration, ringless etc) but in truth we can never know. It is certainly more complicated than I had appreciated.

Sorry if this is a bore or a turn off, but after reading about hack pen absentees and hybrid confusion, I think it is all very diificult.

Having said that, when birds are missing you would think the falconer's would make a bee-line for they are worth up to £10,000 and more! Wild birds very likely do reach our shores as they are great wanderers and dispersed immature birds often spend time in a pelagic way.

Be interested if anyone who understands this wonderful species has any thoughts about the incidence of Gyr in the UK. If not no problem, I can read it back to my self a few times !!:t:

 

[acorn]

Hack pens are just that extremely large pens in which falcons can fly and exercise. But they are just that pens which are enclosed and the falcons are kept captive. And not to be confused with wild hack, where falcons are placed on a hack station several days before they are due to fledge, but are capable of pulling food for themselves. They fledge from these stations and returned to feed at these stations, they are left at liberty
till they start to show signs of becoming independant, then caught back up on the hack station with a bow net.
Regards
Colin
PS at close hand it is pretty easy to spot Saker in a Gyr to an expert eye, the arabs are masters at it.

 

[acorn]

Falcons that are that are wild hacked are perhaps out from late may till late august just depends on their hatch dates. So from september to feb there is no chance of seeing a falcon out at hack, remember falcons at hack will also all be juvenile. That just leaves lost Captive falcons. Mature Gyr falcons sighted at anytime if they seem to lack all equipment jesses anklets, bells, closed rings and transmitter, have a very good chance of being a genuine wild falcon there is a few around. Hope this helps.
Regards
Colin

 

[Lawts]

Perhaps supporting what Wolfbirder is saying there were a staggering 22 individual sightings in 2009, (8 tickable, 7 non-tickable and 7 possibles). There may of course have been some overlap.

5 different birds already in 2010 after only 24 days!!

 

[wolfbirder]

Thanks for your input guys. Appreciate your hack pen detail Colin, really useful knowledge. On a falconry forum i was reading opinion about the recent December Glamorgan bird. Ok it is more difficult to tell from a few still 'perched' photos, but one falconer who had lost a 50-50 Gyr-Saker cross in the Gower area reckoned it was either a 7/8th's or a pure Gyr, another reckoned it could be an hybrid.They commented that only a select few falconer's could actually tell the difference, but I am very interested in what you say, though surely it must become more difficult the higher the ratio of Gyr gene split mixed with a lower Saker gene split?

To further complicate matters, most uk suspected wild bird sightings comprise of immature/1st winter birds, probably if they are wild this makes sense as they will have been displaced from breeding grounds.

 

[wolfbirder]

Adding to this, I have been looking closely at any photos of pure 'white' Gyr's and hybrids but still it is virtually impossible to distinguish due to individual bird variation in size and plumage.

Pure Gyr's are more likely very stocky and less tapered to the rump than typical hybrid Gyr-Sakers, tho this may be indistinguishable when the hybrid is 7/8th and upwards. Slimmer male or immature pure Gyr's may also be suggestive of hybrid in shape. It is estimated that upto 50% of young raptors die in their first year of starvation, so again immature Gyr's seen may well be on the slim side. I also believe photos can be very deceptive regards stockiness, depending on whether the bird is standing and alert, or photographed relaxed and squat, where the body bulk can be 'squashed' out. Classic Gyr's (especially females) are often broad backed and broad chested. As fully grown Gyr's can be 50% heavier than fully-grown Sakers, it may be possible to see Saker genes in hybrids, but is this possible when the gene split is a high ratio to Gyr?

Wing tip-to-tail ratio is also deceptive when studying photos, it is suggested that Gyr-Saker hybrids may have longer wing tips that lie virtually equal to the tail end on a perched bird. But both Gyr & Saker are relatively short-winged birds, again photos can be deceptive anyway with wing to tail positions not being definitive in any way, as photographs can capture birds in different perched positions or stances.

Both pure Gyr's and hybrids can have subtle spotting to flanks, and both can show limited barring to uppertail, but this latter fieldmark is said to be a good feature for pure Gyr. But I have seen photos of pure & hybrid Gyr-Sakers with considerably reduced uppertail barring, and I have also seen photos of immature pure Gyr's with strong uppertail barring. Some hybrids may have largely darker upper tails with narrower pale banding.

Upperparts patterning can help a bit, with it being suggested that hybrids show a mixture of blackish brown & reddish brown patches instead of uniformly brown patches on a white back, but I have not found this easy at all.

Hybrid Gyr-Sakers may well possess a subtle moustachial stripe, but again the difference is so slight this can be difficult to ascertain. Pure white Gyr's should show no sign of moustachial stripe.

Pure Gyr's should possess large, broad heads, but yet again hybrids can show this feature.

Flight profile may be the best determiner, 'classic' pure Gyr's should show broad or wide based wings, & a sort of hunched up peregrine-like appearance.

Of course it is important to establish whether a bird is ringed, if it is not it is likely to be a pure Gyr, but that aside I still feel distinguishing some less classic Gyr's from hybrid Gyr-Sakers is going to be virtually impossible. Ideally a pure white Gyr should be large, broad backed and broad chested, with broad-based wings, large head devoid of any sign of moustachial stripe, uniformly coloured brown on white upperparts, and uppertail that is partially (in many juveniles/immatures) or almost completely devoid (in many adults) of barring.

Gyr-Saker hybrids 'may' show hint of moustachial stripe on a slightly smaller proportioned head, slightly longer and narrower-based wings, possibly a more obviously barred tail, more rufous brown patches on upperparts, and a more tapered shape.

As you can tell, I am fascinated by Gyr's. I may be alone here, but would welcome any other tips people feel may help, especially those who actually know the birds well - which I do not! To me, it is about the balance of probability, with a combination of features rather than any single one, being key identification markers.